[wasm] Fix exception section code for spec compliance.

R=clemensh@chromium.org
BUG=v8:8091

Change-Id: Ib0e0b50d1fe24b0e528a3dd9849829799b33f1bc
Reviewed-on: https://chromium-review.googlesource.com/c/1355139Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57945}

src/wasm/module-decoder.cc

@@ -31,8 +31,6 @@ namespace {
 
 constexpr char kNameString[] = "name";
 constexpr char kSourceMappingURLString[] = "sourceMappingURL";
-constexpr char kExceptionString[] = "exception";
-constexpr char kUnknownString[] = "<unknown>";
 
 template <size_t N>
 constexpr size_t num_chars(const char (&)[N]) {
@@ -83,14 +81,14 @@ const char* SectionName(SectionCode code) {
       return "Element";
     case kDataSectionCode:
       return "Data";
+    case kExceptionSectionCode:
+      return "Exception";
     case kNameSectionCode:
       return kNameString;
     case kSourceMappingURLSectionCode:
       return kSourceMappingURLString;
-    case kExceptionSectionCode:
-      return kExceptionString;
     default:
-      return kUnknownString;
+      return "<unknown>";
   }
 }
 

src/wasm/wasm-constants.h

@@ -71,8 +71,8 @@ enum SectionCode : int8_t {
   kElementSectionCode = 9,     // Elements section
   kCodeSectionCode = 10,       // Function code
   kDataSectionCode = 11,       // Data segments
-  kNameSectionCode = 12,       // Name section (encoded as a string)
-  kExceptionSectionCode = 13,  // Exception section
+  kExceptionSectionCode = 12,  // Exception (aka. event) section
+  kNameSectionCode = 13,       // Name section (encoded as a string)
   kSourceMappingURLSectionCode = 14,  // Source Map URL section
 
   // Helper values

test/mjsunit/wasm/wasm-constants.js

@@ -64,7 +64,7 @@ let kStartSectionCode = 8;       // Start function declaration
 let kElementSectionCode = 9;     // Elements section
 let kCodeSectionCode = 10;       // Function code
 let kDataSectionCode = 11;       // Data segments
-let kExceptionSectionCode = 13;  // Exception section (must appear before code section)
+let kExceptionSectionCode = 12;  // Exception section (must appear before code section)
 
 // Name section types
 let kModuleNameCode = 0;